A(1) Field of the invention
The invention relates to an arrangement for generating a clock signal from a received biphase-modulated signal, comprising a controllable clock signal source.
Arrangements of such a type are suitable for application in arrangements for receiving digital signals which are, for example, used in the subscriber sets of digital telephone systems.
A(2) Description of the prior art
To recover the clock signal in a digital base-band transmission system, use is frequently made of non-linear processing of the received signal, optionally after this signal has been equalized, for generating spectral comonents at the bit repetition rate. A phase-locked loop (PLL) can be driven by the signal thus obtained.
When quantized feedback equalization is used or when a time-discrete echo cancellation system is applied, the signal to be used for the clock signal generation includes signal components produced by the local clock. In that case the clock generation method described above can still be used when the time-discrete portion of the receiving system operates with an adequately high sampling rate. In the case of biphase-encoded signals the processing rate is then four times the bit repetition rate.